Auxiliary scrap feed for plastic molding machines



Aug. 14, 1945. w. o. NICHOLS 2,382,655

AUXILIARY SCRAP FEED FOR PLASTIC MOLDING MACHINES Filed Feb. 16, 1945 INVENTOR, [5/4/1 60 Mafia/J.

Aug. 14, 1945. J w. o. NICHOLS 2,332,655

AUXILIARY SCRAP FEED FOR PLASTIC'MOLDING MACHINES Filed Feb. 16, 1943 Patented Aug. 14,

UNITED STATES PATENT OFFICE 2,382,655 AUXILIARY sonar scan roa rms'nc MOLDING moms Warren 0. Nichols, Los Angeles, Calif assignor to Allied Plastics Company, Los Angeles, Calif., a

copartnership comprised of Dwight C. and Harry G. Long Application Februarylfi, 1943, Serial No. 476,098

2 Claims; (01.18-30) channel into which the thermo-plastic material is injected from the injection cylinder. When the die is opened and the product removed therefrom, it consists of a plurality of'artlcles interconnected by a central sprue and radial runners, which have been formedwithin the above-mentioned central channel and radial passageways leading to the die cavities. The finished articles are severed from the runners and sprue, and the latter becomes reclaimable scrap material.

The object of the present invention is the provision of simple and effective means by which this scrap material maybe ied immediately back' into the molding machine.

The scrap material mentioned is of such a nature that it could not be fed "directly into the main feed hopper, along with the -virgin granular thermoplastic material. In accordance with the present invention, a second or auxiliary-hopper is provided for this scrap material, and this auxiliary hopper leads via a power-driven chopper to the same conveyor means that advances the.

virgin material from the main feed hopper toward the injection cylinder. The power-driven chopper is designed to chop the scrap material into a grain size adequately fine to be handled by the machine. The operator thus deposits the runners and sprue severed from the finished articles immediately into the auxiliary or scrap feed hopper, thereby reclaiming'the scrap material without further handling.

Further objects and accomplishments of the invention involve the means by which the main and auxiliary hoppers both feed a common screw conveyor means, whereby assurance is always maintained that the full output of the chopper will be accepted by the screw conveyor, to the end that any possible choking oi thehopper is avoided.

The invention will now be best understood by referring to the following detailed description of one illustrative embodiment thereof. reference for this purpose being had to the accompanying the injection type, andslnce such machinesare well known in the art, it will be unnecessary to disclose or describe a complete molding machine herein. Accordingly, I show in Fig. l of the drawing, entirely in diagrammatic form, so much 01 a typical molding machine as is necessary to' illustrate the application thereto of the present invention. Moreover, since the application of the present invention is the same with the extrusion type oi machine as with the injection typeclt will be unnecessary to illustrate both herein, and I have accordingly chosen to illustrate the invention in connection with the injection typ of machine, though without necessary or implied limitation thereto.

Numeral I0 having main feed hopper I I, downwardly extendingchannel, conduit or chute i2, leading from the lower end of hopper ll. cylindrical screw conveyor chamber i3 receiving material from channel ,i 2,, out1et passageway i4 leading from one end of vconveyor';chamber l3, and heating and injection cylinder l5 arranged to, receive material from passageway l4. Reciprocable within cylinder IE is the usual ieeding ram l6, operable in a conventional manner by means oi a pressure piston, not illustrated, within work cylinder l1. Screw conveyor it within conveyor chamber [3 is on a shaft it, here illustratively indicated as driven through magnetic clutch 20 and belt 2i from the shaft 22 of electric drive motor 23. Motor 28 operates continuously, and at the time in the operating cycle that the material is to be fed into cylinder l5, ram It being at such time in retracted position, magnetic clutch 20 is energized through automatic switching arrangement not necessary here to detail, thereby coupling the screw conveyor to motor 23 and effecting a feed of material from supply conduit l2 towards passageway to, discharging into cylinder i5. Magnetic clutch remains energized for a predetermined time interval eilecting a delivery; of a predetermined charge 0! the material into cylinder it, after which the clutch 20 is automatically de-energized, and the feeding operation of screw conveyor i8 is arrested. This magnetic clutch, if used, may be energized and deenergized at proper times designates generally a fragmentary portion of a typical injection molding machine,

through appropriate contacts incorporated in the electric timer conventionally provided in molding machines of the type in question, as will be readilyunderstoodbythoaeskilledinthe art. Any alternative means or well known or appropriate character for accomplishing intermittent ieed oi the material from simply conduit I! to injection cylinder ll may 01 course be substituted, the particular means (or feeding the material forming no part of the present invention, and being subiect to any desired work-out.

The plastic molding machine described in the foregoing is quite conventional, and merely illustrative oi one typical type of machine to which the invention may be applied. A typical embodiment oi the present invention, as applied to said illustrative molding machine, will now be described. 1

As will be noted in the drawing, theiuncture main ieed conduit I! with conveyor cylinder I3, is, in accordance with the invention, located at a point spaced somewhat from the rearward end of cylinder II, and communicating with cylinder, at a point preferably rearwardly of the junction point between conduit i2 and cylinder II, is an auxiliary iced conduit III, the latter receiving chopped scrap material from a chopper generally designated as Ii, and which receives such material !rom scrap iced hopper l2. The chopper, is showntocompriseahousing ll havinganinlet 34 at the top, to which is joined the neck II of hopper SI, and an outlet 86 at the bottom Joined to the upper end of conduit 30. Inlet it thus leads to the interior chopper II and outlet ll asses the chopped material toconduit 30. Main feed conduit i! may be arranged in any suitable manner so as to avoid interference with the chopper and auxiliary hopper II; for instance, it may be arranged somewhat to the rear of the chopper, and may have a sloping oilset section as at Ila. Hmisingueontainsasetoistationarykniyes,indicated at II, and cooperating therewith are a piuralityorrotatingknivesli mounted onacenner;iorinstance,ashere cally indicated. it may be driven through bevel gears 48' andlliromashaitll,whichisinturndriven rrommotorshaitllthroughbeltllandsuitable pnlleysllandll. nscreenleotpropermesh, for instance V4". is mounted in outlet 00. and preventsdischarseotmaterialuntilgrmmdtothe neeessarydcgreeoinneness,

lnoperamthevirgingranuiar thermoplasticmaterialisiedmtomaini'eedhm rlLand nowsdownwardlythereiromviaoondint llto asaaess main teed conduit normally is,nlled with material from hopper H, and hence tends to fill the ts shaft is which is driven in any suitable man- 7 bore of cylinder It. It the auxiliary scrap ieed conduit were to communicate with cylinder ll between conduit i2 and the discharge end or the cylinder, some-difliculty milht therefore, be encountered in that the cylinder would tend to be choked with material received from conduit it to such an extent that it could not readily accept the ground scrap. But by locating the scrap iced inlet to cylinder i3 rearwardly oi the point at which material is led into the cylinder from conduit i2, no such difliculty is encountered, and the conveyor cylinder accepts the material ted to it by both conduits l2 and II, the conveyor screw ll advancing the material received from the scrap feed and commingling it with the virgin material received from the main inieed. Theamount or the latter material entering cylinder it is of course reduced to an extent lust equal to the amount of ground scrap fed in'via conduit 30. The improvements provided by the present invention greatly facilitate the handling or the reclaimable scrap material produced in plastic molding. The operator removes the iinished product from the machine, immediately clips the runners and sprue from the finished articles, places thelatterinabinorouaconveyorhelt,

feed hopper". Thematerialisthusimmediately re-run throush the machine. The problelnoi handlingthescrap outmltoithemachine is thus solved in a moat eilective and eiiieient manner.

I claim:

Llnapiasticmoidingmachinehavingadie cavity, a main inieed hopper, a cylindricaiconveyer chamber having longitudinally spaced inlet and outlet openinss, a screw conveyer in said chamber, a material passageway connecting said main inieed hopper with said inieed opening at said chamber, and a material passaaeway leading from said discharge opening of said chamber toward said die cavity: an auxiliary inieedhop- 'per for scrap material. chopper means tor chopconveyor cylinder". 'Attimesoienergisationoi spaced pingmaterialiedintosaidanxiliaryhoppertoa predetermineddegreeolnnsnmandamaterill passsgewayiorconveyingehcppedmatenalircm saidchoppinsmeanstosaidconveyerehamber,

atapointspacedbeyondsaidinletopeninaimm' saidoutletonlm l 2.Inapiasticmoldingmachine,aeyiindrieal conveyor chamber iormed with lonsitudinaliy mainintakeanddischargeopeninaaand withanauxiliaryintakeopeningspacedbeymd saidmainintskeopeningiromsatddischarseo ening.'saidmainintaseopenimbeingadsntid toreceivevirginthermopissticmatcriai,ascrew conveyerinsaidehsmbenaninieedmeanstcr jscrapmateriahchoppingmeansiorcboppingmaterialiedintosaidinieedmeanaandapassaeewayiorconveyingmaterialchoppedbysaid chopping means to said'auxiliary intake openinainsaidchamber;

WARREN O. NICHOLS. 

